Which 6.0l LS engine???

[Rick D]

Originally Posted by PTAddict

As you can probably derive from this thread, for a normally aspirated build, the priority order as a starting point would be:

1. LY6
2. LQ9
3. LQ4

The LY6 has the later rectangular port L92-style heads, and therefore the most power potential. In my 2nd gen, I have an LS3 crate motor, 6.2L with L92/LS3 heads and LS3 intake, mild 227/235 cam, made 460 HP at the rear wheels thru T56 with a conservative tune, otherwise stock. The LY6 has lower compression (9.6 vs 10.8) and .2L less displacement, but I'd say 410 - 430 RWHP or more is still easily in reach with equally mild cam kit. And it would run pretty well on cat-pee 87 octane.

The LQ9 has one primary advantage over the LQ4 - more compression (10.0 vs. 9.4, IIRC). The extra compression might be worth 10 HP or so.

The LQ4 is still a very strong option, and more available than the others. I've seen ~385 RWHP with a very mild cam, LS6 intake, thru stock 4L65E (probably over 400 with a stick). To put that in perspective, I can't recall seeing more than about 330 RWHP from any of the iconic muscle cars we've tuned - Hemi, Six-Pack 440, 454 LS6, etc. And once again, 87 octane won't cost much if any power.

As an aside, the lower compression of these truck engines makes them great candidates for a blower. Put a Magnuson, Edelbrock, Whipple on a stock late model LS6 or LS3, and the power potential gets severely limited by knock retard due to the high static compression ratio. My biz partner's Z06 would only take about 8 degrees timing under 6 PSI boost before we hit knock, limiting us to about 480 RWHP. I'd bet we get easily over 500 with an LQ4 as a base, and the torque curve would be awesome.

Thanks for the info, nice write up.

We put a 2001 ls1 with milled down 5.3 heads through LS6 intake and a nice cam, through a 4 speed manual trans. Made 426 rwhp!

[COYBILT]

All the engine choices you have picked are great candidates. My only advice is Do Not stick l92 heads on a 6.0L. Especially in a heavy car. The port velocity isnt there, The l92s have vvt to take care of the gigantic intake ports of the l92 heads. The l92s also have a larger bore to help unshroud the valve. The 6.0 can make awesome power with just a cam change and some long tubes. The cathedral based heads are a great unit wether they be 243 castings or 317s. I personally made 591 at the tire with a ls2 with a 239/243 @.050, magnuson 122 and kooks long tubes with a 1 7/8 primary. I would vote on the lq9 with a cam change and headers, unless you want to start playing with heads. You really can't go wrong with any of them, the LSX family is just awesome hands down.

[fleetus macmullitz]

Originally Posted by Rick D

Thanks for the info, nice write up.

We put a 2001 ls1 with milled down 5.3 heads through LS6 intake and a nice cam, through a 4 speed manual trans. Made 426 rwhp!

Very nice #'s from a basic combo.

[Rick D]

Originally Posted by compos mentis

Very nice #'s from a basic combo.

Yeah we were blown away with those numbers. It was a big cam!!